Stationary sources around the world will spend $11 billion in 2014 for capital equipment and consumables to control NOx. This is the latest projection in NOx Control World Markets published by the McIlvaine Company.

World Stationary NOx Control Expenditures $ Millions in 2014

Industry

SCR/SNCR

Catalyst

Reagent

Total

Utility Power

6,500

1,100

1,300

8,900

Other

1,500

100

500

2,100

Total

8,000

1,200

1,800

11,000

The utility industry will be the biggest purchaser accounting for 81 percent of the total. Industrial boilers in pulp and paper, chemical and other industries will be the second largest purchasing category. Cement plants will be a relatively small purchaser of hardware but will account for nine percent of the reagent consumption. The reason is that cement plants are opting for the lower capital cost SNCR systems. SNCR requires significant reagent per ton of NOx removed.

At one time, only a small percentage of gas turbines were fitted with SCR. However, recently many new turbines are being equipped with SCR. At one time, peaking turbines were not equipped with SCR because they only operate for a portion of the year and so are generating more modest NOx quantities. However, recent regulations in the U.S. have forced the use of SCR on these peaking units. The use has even spread to gas turbines operating on Floating Production, Storage and Offloading (FPSO) units operating in the U.S. Gulf.

China is the leading purchaser of SCR and SNCR systems but is still lagging the U.S. in terms of catalyst and reagent purchases. However, based on its aggressive program to equip new facilities with NOx control and to retrofit many other facilities, it will soon pass the U.S. in terms of catalyst and reagent purchases. A number of catalyst manufacturing facilities are now in operation in China. Additional facilities are under construction to meet the rapidly increasing demand.

Urea is the reagent of choice for SNCR systems. Anhydrous ammonia, aqueous ammonia and urea are all options for use with SCR systems. The urea is converted to ammonia on-site. This option is popular when there are safety concerns. It is also popular where there are ammonia supply problems. Chinese power plants have generally favored the use of urea with on-site conversion facilities. Aqueous ammonia is more expensive than anhydrous but is used where there are safety concerns relative to the use of anhydrous. Compared to urea, there are no capital costs for conversion.

SNCR is selected for those applications where the efficiency requirement is relatively low. Where the efficiency requirement is above 80 percent, SCR is the choice. SCR is also required when low outlet emissions are required regardless of the efficiency.